The present invention relates generally to a backplane of an industrial computer system, and particularly relates to a modular backplane comprising a plurality of backplane segments which are bridged together by a low-profile bridge module.
Conventionally, a computer system utilizes a bus as a pathway or channel for data communication among the components of the system. A popular bus architecture is the PCI (Peripheral Component Interconnect) bus architecture. The PCI bus standard (specification) is well suited to personal computers. There are, however, numerous limitations of the PCI bus specification that make the bus impractical for industrial computers.
In order to provide a standard form factor for industrial computers, the PCI Industrial Computer Manufacturers Group (PICMG(trademark)) has prepared the Compact PCI Specification that employs mechanically robust connectors and has a bus that conforms to the PCI Specification. This Compact PCI bus architecture is an implementation of PCI technology designed for industrial and/or embedded applications. The Compact PCI standard also has limitations on certain design aspects, such as the number of slots on the bus. More specifically, the Compact PCI standard defines that the PCI compliant bus has a maximum of eight electrical loads. This means that the backplane of a computer system is limited to have a maximum of eight slots.
Accordingly, it would be desirable to be able to provide a backplane of an industrial computer with more than eight slots (electrical loads). Several attempts have been made for provision of more than eight slots on the backplanes of industrial computer systems.
One of the most recent attempts is illustrated in FIGS. 1A to 2B, which is described in U.S. application Ser. No. 09/538,733 of Steven J. Mercer, et al., filed on Mar. 30, 2000. As shown in the figures, this approach relates to a modular backplane having two or more backplane segments, which are bridged by a bridge module and, respectively, include a PCI compliant bus, although the figures illustrate only two backplane segments for convenience of description. The modular backplane 10 comprises two backplane segments 20 and 40 bridged by a bridge module 60, where the segment 40 acts as a primary or beginning segment and the segment 20 as a secondary or ending segment, which means that a system board is supposed to be inserted into the beginning segment 40. FIGS. 1A and 1B show a configuration of the front side and back side of the segments. Each segment has a front side 22 (44) and a back side 24 (44) and the front sides 22, 42 includes several slots (S1 to S7), which are for the insertion of a system board and peripheral boards. Each of the slots consists of five connectors (J1 to J5). FIG. 2A shows the back sides 24, 44 of the backplane segments 20, 40 bridged by the bridge module 60, and FIG. 2B is a frontal elevation view of FIG. 2A. As is shown in FIGS. 1B and 2A, the back sides 24, 44 of the segments 20, 40 also includes several slots (S1 to S7 respectively) of two different lengths, in which the long slot 46, 48 in the primary segment 20 and 26, 28 in the secondary segment 40 serve as bridge modular slots for the insertion of the bridge module 60. More specifically, the connectors J1 and J2 of the slots 26, 46 denote a bridge module primary slot, and the connectors J1 and J2 of the slot 28, 48 denote a bridge module secondary slot. The remaining short slots may be utilized for other add-in cards such as a transition module.
As depicted in FIGS. 2A and 2B, the bridge module 60 comprises a circuit board 62, a bridging IC 64, and a pair of connectors 66a, 66b. The connector 66a is engaged with the bridge module primary slot 46 of the primary (or beginning) backplane segment 40, while the connector 66b is engaged with the bridge module secondary slot 28 of the secondary (or ending) segment 20, as is clearly depicted in FIG. 2B. Therefore, a busing between the primary and secondary backplane segments 40, 20 has been established. In the case shown in the figures, a system board may be inserted into the slot S7 of the front side 42 of the primary backplane segment 40, which is exactly opposite to the bridge module secondary slot 48. By using another bridge module, another backplane segment may be connected to the right side of the secondary (ending) segment 20 in FIG. 2A, such that two or more backplane segments can be communicatively interconnected to each other by bridge modules, thereby providing more than eight slots (electrical loads) on the backplanes of industrial computers.
However, this approach embraces several disadvantages that must be solved. Firstly, it is inevitable that the back side bridge slot share its pins, in part, with the front side peripheral board slot, backwardly opposite to the bridge module slot. Therefore, the type of the board to be inserted into the front side peripheral board slot is limited. Also, the signaling of the bridge module is limited by that of the peripheral board inserted into the front side slot, and vice versa. Secondly, as is shown in FIG. 2B, it is also unavoidable that the bridge module, when engaged, protrude excessively over the height of the back side bridge slot. This implementation does not meet the governing standard (IEEE 1101.11), which allows for components of the backplane to protrude no more than 19.94 mm, measured from the front surface of the backplane. The bridge module of this technology protrudes around 24 mm from the front surface of the backplane. Furthermore, the protrusion of the bridge interferes potentially with the insertion of add-in cards, such as transition modules, into the back side slots.
In accordance with an aspect of the present invention, there is provided a modular backplane for an industrial computer, in which the modular backplane comprises a first modular backplane segment, a second modular backplane segment and a bridge module. The first modular backplane segment includes a first front side and a first back side, in which the first front side has a plurality of slots, and the first back side has a first dedicated connector. The second modular backplane segment includes a second front side and a second back side, in which the second front side has a plurality of slots, and the second back side has a second dedicated connector. The first and second dedicated connectors are provided in an area where no slot is formed. The bridge module includes a pair of connectors. One of the bridge connectors is engaged with the first dedicated connector and the other is engaged with the second dedicated connector, such that the first and second modular backplane segments are connected to each other communicatively.
The slots provided in the first front side may provide for the insertion of a system slot board and a plurality of peripheral boards and all of the slots in the second front side may provide for the insertion of a plurality of peripheral boards, and vice versa. The first back side and the second back side each may further include a plurality of slots, which may provide for the insertion of add-in cards such as a transition module.
Preferably, the modular bridge is of a low-profile, such that the height of the bridge module is less than 16 mm, the width less than 12 HP, and the length less than 94 mm. The first and second dedicated connectors are formed in an area where no slot is formed.
In accordance with a further aspect of the present invention, there is provided a modular backplane for an industrial computer, in which the modular backplane comprises a plurality of modular backplane segments and a plurality of bridge modules. Each modular backplane segment includes a front side and a back side, in which the front side has a plurality of slots, and the back side has a primary dedicated connector and a secondary dedicated connector. The primary and secondary dedicated connectors are provided in an area where no slot is formed. Each bridge module includes a pair of connectors. One of the bridge connectors is engaged with the primary dedicated connector and the other is engaged with the secondary dedicated connector in its neighboring segments, and vise versa, such that all the modular backplane segments are communicatively connected.
The slots provided in the front side of one of the backplane segments may provide for the insertion of a system slot board and a plurality of peripheral boards and all of the slots in the front side of the remaining backplane segments for the insertion of a plurality of peripheral boards. The first back side may further include a plurality of slots, which may provide for the insertion of add-in cards such as a transition module.
Preferably, the modular bridge is of a low-profile, such that the height of the bridge module is less than 16 mm, the width less than 12 HP, and the length less than 94 mm. The dedicated connectors are provided in an area where no slot is formed.
Therefore, in contrast to the previous approach, the present invention provides greater flexibility in the type and the number of peripheral boards to be inserted into the front side of the backplane, and in the type and the number of the signals to be accommodated on the peripheral board and the bridge module. Furthermore, it eliminates any interference by the bridge module with the insertion of add-in cards, such as transition modules, into the back side slots of the backplane.
Accordingly, it is an object of the present invention to provide an improved modular backplane configuration having a dedicated connector for a bridge module, in m which a greater flexibility in the type of and the number of slots and the peripheral boards inserted thereto can be allowed in the front side of the backplane segments.
It is another object of the present invention to provide an improved modular backplane configuration having a dedicated connector for a bridge module, in which a greater flexibility in the type and the number of signals can be allowed not only in the bridge module of the back side but in the peripheral board of the front side of the backplane segments.
It is another object of the present invention to provide an improved modular backplane configuration having a dedicated connector for a bridge module, in which the insertion of add-in cards in the back side can not be interfered by the implementation of the bridge module.
It is another object of the present invention to provide an improved low-profile bridge module which can accomplish the above-described objects of the invention.
In accordance with a further aspect of the present invention, there is provided a monolithic backplane for an industrial computer, which includes: a first backplane segment having a first front side and a first back side, the first front side including a plurality of slots, the first back side including a first dedicated connector, a second backplane segment having a second front side and a second back side, the second front side including a plurality of slots, the second back side including a second dedicated connector, a bridge module having two connectors, one of which is engaged with the first dedicated connector and the other is engaged with the second dedicated connector, thereby communicatively connecting the first and second backplane segments. The first and second dedicated connectors are provided in an area where no slot is formed.
A further understanding of the other features, aspects, and advantages of the present invention will be realized by reference to the following description, appended claims, and accompanying drawings.